B2.3 Biogeochemical cycles & carbon reduction Flashcards
Why are biogeochemical cycles important?
Biogeochemical cycles ensure that chemical elements remain available to living organisms.
How can human activity affect biogeochemical cycles?
Human impact can disrupt these cycles, affecting the sustainability of ecosystems.
What are the key components of biogeochemical cycles?
They include stores, sinks, and sources.
What is the difference between a store, a sink, and a source?
A store remains in equilibrium, a sink accumulates an element, and a source releases an element.
Where are organic stores of carbon found?
Organic stores of carbon are found in organisms, crude oil, and natural gas.
Where are inorganic stores of carbon found?
Inorganic stores of carbon are found in the atmosphere, soils, and oceans.
What determines whether a carbon store is in equilibrium?
Equilibrium occurs when carbon absorption is balanced by its release.
What is residence time in the carbon cycle?
Residence time is the average duration a carbon atom remains in a store.
How long would carbon remain in fossil fuels without human interference?
Carbon would remain stored in fossil fuels for hundreds of millions of years.
What processes move carbon between stores in ecosystems?
Carbon moves through photosynthesis, feeding, defecation, cellular respiration, death, and decomposition.
What is the difference between transfers and transformations in the carbon cycle?
Transfers move carbon between stores (e.g., feeding), while transformations change its form (e.g., photosynthesis).
What is carbon sequestration?
Carbon sequestration is the process of capturing atmospheric carbon dioxide and storing it in a solid or liquid form.
How do trees naturally sequester carbon?
Trees absorb carbon dioxide and convert it into biomass through photosynthesis.
How does organic matter contribute to carbon sequestration?
Organic matter can be fossilized over time, forming coal, oil, and natural gas.
How can ecosystems act in the carbon cycle?
Ecosystems can function as carbon stores, sinks, or sources.
What determines whether an ecosystem stores or releases carbon?
If photosynthesis exceeds respiration, the ecosystem acts as a sink. If respiration exceeds photosynthesis, it becomes a carbon source.
How does a young forest function in the carbon cycle?
A young forest acts as a carbon sink, absorbing more carbon dioxide than it releases.
How does a mature forest function in the carbon cycle?
A mature forest acts as a carbon store, maintaining a balance between carbon input and output.
How does a forest destroyed by fire or deforestation function in the carbon cycle?
It becomes a carbon source, releasing stored carbon dioxide back into the atmosphere.
What are fossil fuels in relation to the carbon cycle?
Fossil fuels are stores of carbon with long residence times, formed when past ecosystems acted as carbon sinks.
How do fossil fuels become carbon sources?
When burned, fossil fuels release stored carbon dioxide into the atmosphere.
How can agricultural systems act in the carbon cycle?
They can function as carbon stores, sources, or sinks depending on farming techniques.
What agricultural practices promote soil as a carbon sink?
Regenerative methods like crop rotation, cover crops, and no-till farming increase carbon storage.
What agricultural practices promote soil as a carbon source?
Practices like wetland drainage, monoculture, and heavy tillage release carbon into the atmosphere.
How does timber production affect carbon storage?
Long-term cropping, such as timber production, influences carbon storage based on how harvested products are used.
How does carbon dioxide interact with the ocean?
Carbon dioxide dissolves in ocean water and is released as a gas when it comes out of solution.
Why is the ocean a carbon sink?
The ocean absorbs large amounts of carbon dioxide, but human fossil fuel use releases carbon faster than oceans can absorb it.
What is ocean acidification?
Ocean acidification occurs when increased carbon dioxide dissolves in seawater, lowering pH levels.
How does ocean acidification harm marine life?
Lower pH interferes with calcium carbonate formation, weakening mollusc shells and coral skeletons.
What measures can help reduce human impact on the carbon cycle?
Using low-carbon technologies, reducing fossil fuel use, minimizing soil disruption and deforestation, reforestation, and artificial sequestration.
